Table 2 Clinical features of the proband and his father with PMP22 and SCN4A mutations
Patient | Proband | Proband’s father | |
|---|---|---|---|
SCN4A gene studies | c.3917G > C p. Gly1306Ala | c.3917G > C p. Gly1306Ala | |
PMP22 gene studies | Duplication in PMP22 | Duplication in PMP22 | |
Sex | Male | Male | |
Age (yrs) | 29 | 57 | |
Age at Onset | Adolescence | Unknown | |
First symptom at onset | High-arched feet | High-arched feet | |
Muscular Stiffness | Yes, mostly in the mornings or after long exercises | No | |
Muscle pain | No | No | |
Muscle weakness | Upper limb | Wrist muscles 3/5, intrinsic hand muscles 2/5 | No |
Lower limb | Ankle and toe extensors < 3/5, ankle dorsiflexion restricted | No | |
Muscle atrophy | Mild atrophy of the distal muscles of the hands, subtle wasting of thigh musculature | Very mild distal atrophy of the lower leg muscles | |
Muscle hypertrophy | Mild calves hypertrophy | Very mild proximal hypertrophy of the lower leg muscles | |
Warm up phenomenon | No | Not Applicable | |
Handgrip myotonia | Yes | No | |
Myotonia worsened by cold | No | Not Applicable | |
Myotonia distribution | Hands, arms, legs | Not Applicable | |
Electromyography | Positive for generalized typical myotonic discharges | Myotonic discharges were confirmed in the left biceps muscle | |
CK(U/L) | 224 U/L, 386 U/L | Not examined | |
Pes cavus | Yes | Yes | |
Sensory loss | A stocking-glove distribution involving the upper limbs to the level of the elbows and the lower limbs to the mid-calf | No | |
Deep tendon reflexes | Absent | Absent | |
Plantar response | Flexor | Flexor | |
Sural nerve biopsy | Severe demyelinating neuropathy | Not examined | |
CMTNS | Severe (26) | Mild | |
Recurrent flaccid paralysis | No | No | |
Scoliosis | No | No | |